High Resolution FTIR Spectroscopy Research Articles

Synthesis and Structural Analysis of Novel Neuroprotective Pentacyclo[5.4.1.02,6.03,10.05,9]undecane- and Adamantane-Derived Propargylamines

In this article we present a detailed structural investigation of novel polycyclic pentacyclo[5.4.1.02,6.03,10.05,9]undecane and adamantane propargylamine hybrid molecules. The structural characterization of these compounds was performed using MS, FT-IR and NMR spectroscopy in combination with X-ray diffraction analysis. The single crystal X-ray analyses of four synthons (6, 8–10) are presented; 8-(N)-propargylamino-8,11-oxapentacyclo-[5.4.1.02,6.03,10.05.9]undecane (compound 6 crystallized in the monoclinic system, unit cell parameters: a = 20.737(2) A; b = 8.127(1) A; c = 12.606 (1) A; β = 92.360(2)°; V = 2122.8(3) A3; Z = 8); 11-hydroxy-(N)-propargyl-8,11-azapentacyclo[5.4.1.02,6.03,10.05.9]undecane (compound 8 crystallized in the monoclinic system, unit cell parameters: a = 7.9624(6) A; b = 14.9332(6) A; c = 9.6162(7) A; β = 109.029(3); V = 1080.9(2) A3; Z = 4); 1-methyl-11-hydroxy-(N)-propargyl-8,11-azapentacyclo[5.4.1.02,6.03,10.05.9]undecane (compound 9 crystallized in the monoclinic system, unit cell parameters: a = 7.732(1) A; b = 15.148(2) A; c = 9.864(1) A; β = 101.728(3)°; V = 1131.3 (2) A3; Z = 4); and an adamantane derivative, N,N-dipropargyl-adamantan-1-amine (compound 10 crystallized in the orthorhombic system, unit cell parameters: a = 34.098(4) A; b = 6.825(1) A; c = 10.979(1) A; V = 2555.0(5) A3; Z = 8). From the X-ray analyses it is clear that the polycyclic structures had different modes of intermolecular interaction and molecular stacking. Compound 9 exhibited a cis configuration between the OH and CH3 moieties as expected in view of potential steric hindrance and the electron density effects of the methyl moiety on the initial amination reaction. These hybrid molecules exhibited significant anti-apoptotic activity and could thus find application as neuroprotective agents. A series of pentacyclo[5.4.1.02,6.03,10.05,9]undecane- and adamantane-propargylamines were synthesized and characterized by high-resolution MS, FT-IR, 1H-NMR and 13C-NMR spectroscopy and single-crystal X-ray diffraction. These compounds showed promising neuroprotective ability.

High-resolution FTIR spectroscopy of the ν3 band of methyl acetylene-d

The high-resolution Fourier transform spectrum of methyl acetylene-d1 (CH3CCD) at room temperature has been recorded in the region of the ν3 band (1980–2035cm−1) at an apodized resolution of 0.004cm−1. About 600 vibration–rotation transitions have been assigned, with J upto 36 and K upto 6. The spectrum shows the presence of several perturbations. The observed minus calculated deviation of the fit for K=4 subband is much more than the expected, shows the presence of Fermi resonance with the nearby vibrational state.

Synthesis and Optical Characterization of Sulfonated Polyaniline/Single-Walled Carbon Nanotube/Zinc Sulphide Nanocomposite

Polyaniline functionalized with sulfonate groups (SPANI) shows excellent solubility in water. Single-walled carbon nanotubes functionalized with carboxylic groups (f-SWCNTs) and then hybridized with freshly prepared zinc sulphide (ZnS) nanocrystals have been found to be good luminescent material with tuned emission properties. Nanocomposite of sulfonated polyaniline with embedded SWCNT/ZnS nanohybrid fibers has been prepared by a simple solution mixing process and characterized by using high resolution transmission electron microscopy (HRTEM), X-ray diffractometry, Raman spectroscopy, FTIR spectroscopy, and thermogravimetric analysis (TGA). The study of optical properties by UV-vis absorption and photoluminescence spectroscopy reveals that the composite is a luminescent material of enhanced emission intensity in the visible region of the spectrum.

On the Road from Formamide Ices to Nucleobases: IR-Spectroscopic Observation of a Direct Reaction between Cyano Radicals and Formamide in a High-Energy Impact Event

The formamide-based synthesis of nucleic acids is considered as a nonaqueous scenario for the emergence of biomolecules from inorganic matter. In the current study, we scrutinized the chemical composition of formamide ices mixed with an FeNi meteorite material treated with laser-induced dielectric breakdown plasma created in nitrogen buffer gas. These experiments aimed to capture the first steps of those chemical transformations that may lead to the formation of nucleobases during the impact of an extraterrestrial icy body containing formamide on an early Earth atmosphere. High-resolution FT-IR spectroscopy combined with quantum chemical calculations was used to analyze the volatile fraction of the products formed during such an event. We have found that the spectrum of the evaporated formamide ices is dominated by the spectral signatures of the dimeric form of formamide. Upon exposure to laser sparks, new well-defined bands appear in the spectrum centered at ~820, ~995, and ~1650 cm(-1). On the basis of quantum chemical calculations, these bands can be assigned to the absorptions of 2-amino-2-hydroxy-acetonitrile and to 2-amino-2-hydroxy-malononitrile, which are formed in a direct reaction between formamide and CN(•) radicals upon the high-energy impact event. We also show that there is an exergonic reaction route via these intermediates leading to diaminomaleonitrile, which is generally considered to play a key role in the synthesis of nucleobases.

Tunneling and Tunneling Switching Dynamics in Phenol and Its Isotopomers from High‐Resolution FTIR Spectroscopy with Synchrotron Radiation

Tunneling and chemical reactions by tunneling switching are reported for phenol and ortho-deuterophenol on the basis of high-resolution FTIR spectroscopy. Tunneling splittings are measured for the torsional motion in the ground and several vibrationally excited states of phenol. Tunneling times range from 10 ns to 1 ps, depending on excitation. For more-highly excited torsional levels in ortho-deuterophenol, delocalization and chemical reaction by tunneling switching is found.

High resolution FTIR spectroscopy of chlorofluoromethane near 13 µm: rovibrational analysis and resonances of ν5 and 2ν 6 bands in ClF and ClF

The FTIR spectra of CH2ClF (natural isotopic mixture) and ClF (isotopically enriched sample) were investigated in the ν5 and 2ν6 region between 700 and 800 cm−1 at a resolution of 0.004 cm−1. The ν5 and 2ν6 vibrations of A′ symmetry give rise to a/b hybrid bands with a very predominant a-type component. Due to the proximity of their band origins, the v 5 = 1 and v 6 = 2 levels perturb each other by Fermi and Coriolis resonances. The interaction mechanisms, previously investigated in the rotational spectra of ClF, were extended to the less abundant isotopic species ClF and to higher J and Ka values in the main isotopologue. The spectral analysis resulted in the identification of 4188 and 5392 transitions for ClF and ClF, respectively. All the assigned data were simultaneously fitted using the Watson's A-reduction Hamiltonian in the I r representation and perturbation operators. Excited state parameters, band origins and coupling terms for the ν5/2ν6 dyad of both isotopologues were determined.

High-resolution FTIR spectroscopy of the ν7 and ν8 bands of 1-phosphapropyne

1-Phosphapropyne has been prepared and high-resolution (0.001cm−1) spectra have been recorded on the far-infrared beamline at the Australian synchrotron between 1500–700cm−1 and 400–50cm−1. Ro-vibrational transitions of the ν8 (308cm−1) and ν7 (1006cm−1) fundamentals as well as the 2ν8±2←v8±1 and 2ν80←v8±1 hot-bands have been assigned, and rotational, centrifugal distortion and Coriolis interaction parameters determined. The 2ν8±2←v8±1 hot-band is an example of a particularly complex E←E transition, for which both states are strongly Coriolis and l(2,2) coupled.

Laser Spark Formamide Decomposition Studied by FT-IR Spectroscopy

High-resolution FT-IR spectroscopy was used for the analysis of the products of formamide dissociation using a high-energy Asterix laser. In the experiment, the detected products of the formamide LIDB dissociation were hydrogen cyanide, ammonia, carbon monoxide, carbon dioxide, nitrous oxide, hydroxylamine, and methanol. The molecular dynamics of the process was simulated with the use of a chemical model. The chemistry shared by formamide and the products of its dissociation is discussed with the respect to the formation of biomolecules.

Oxygen-isotope labeled titania: Ti18O2

(18)O-isotope labelled titania (anatase, rutile) was synthesized. The products were characterized by Raman spectra together with their quantum chemical modelling. The interaction with carbon dioxide was investigated using high-resolution FTIR spectroscopy, and the oxygen isotope exchange at the Ti(18)O(2)/C(16)O(2) interface was elucidated.

High-resolution FTIR spectroscopy of CH2D35Cl: analysis of the nearly degenerate v 4 and v 8 levels

The high-resolution (0.005 cm−1) FTIR spectrum of CH2D35Cl has been investigated between 1160 and 1360 cm−1, the region of the ν4 (A′) and ν8 (A″) fundamentals. The ν4 mode is expected to show an a/b-hybrid band, whereas ν8 should generate a pure c-type envelope. The rovibrational levels (Δν0 for the deperturbed band centres is 0.66 cm−1 only) interact through a-and b-type Coriolis resonances. As a result, the P branch of the ν4 b-type component and the R branch of the ν8 c-type band are missing. In addition, the ν8 mode gives rise to a weak pseudo a-type component still deriving from interaction with ν4. Because of closeness of the two vibrational states, several ΔKa = 0 crossings occur between sublevels of different parity. The data set, composed of 3641 transitions of ν4 and 2624 of ν8, was fitted using Watson's A-reduction Hamiltonian in the Ir representation implemented with first and higher order a- and b-Coriolis coupling terms. Accurate upper state molecular constants, including all quartic centrifugal distortion parameters, and six coupling coefficients have been determined.

Solvothermal Synthesis of TiO2 Nanocrystal Colloids from Peroxotitanate Complex Solution and Their Photocatalytic Activities

TiO2 nanocrystal colloids with different shapes and sizes have been prepared from a peroxotitanate complex solution starting from titanium(IV) sulfate and hydrogen peroxide (H2O2) in water/alcohol media by a solvothermal process. The TiO2 nanocrystals were characterized by transmission electron microscopy, high-resolution transmission electron microscopy, X-ray diffraction, FT-IR spectroscopy, zeta potential, and nitrogen adsorption. The TiO2 nanocrystal colloids prepared by a solvothermal process at 120 °C show a highly crystallized anatase phase. The particle sizes decreased with the increase of the alcohol/water ratio. The shapes of the particles have been controlled from the “rodlike” in pure water solvent to a “rectangular” shape in pure ethanol solvent. The photocatalytic activities of TiO2 nanocrystals were evaluated by the degradation of phenol. The photocatalytic activity of the anatase nanocrystal was closely related to the particle diameter. In addition, the possible growth mechanism of this an...

Electrochemically induced bioactivity of porous silicon functionalized by acetylene

AbstractIn order to improve the bioactivity of porous silicon chemically functionalized by acetylene (PSi–C) and stimulate the calcium‐phosphorous (hydroxyapatite) deposition on this material from a simulated body fluid, electrochemical oxidation of the PSi–C templates has been employed. The initial functionalization by acetylene was done at 500 °C in a N2 + C2H2 gas stream of 1:1 ratio for 15 minutes; further electrochemical oxidation was performed in 80% phosphoric acid. The morphology and chemical composition of initial and oxidized porous structures were studied by the high resolution SEM technique and FTIR spectroscopy. Initial chemical functionalization leads to a very stable (practically bio‐inert) material that after electrochemical oxidation becomes bioactive. We observed that the hydroxyapatite phase has been homogeneously deposited on the electrochemically oxidized PSi–C material immersed in the SBF of Kokubo formulae at 36.5 °C just after two weeks. The layer of hydroxyapatite grown on the surface after 30 days of immersion was compact, crystalline and as thick as 5 μm. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Study of vibration–rotation levels in formamide with high resolution FTIR spectroscopy: The ν12, 2 ν12, ν11, and ν9 bands

The far infrared and infrared spectra of formamide (HCONH 2) have been recorded at high resolution (0.00125 cm −1) in the region of 90–1060 cm −1. Over 20,000 transitions from the out-of-plane NH 2 wagging motion ( n 12 = 1 ← 0 fundamental, n 12 = 2 ← 0 overtone, n 12 = 2 ← 1 difference bands), torsion ( n 11 = 1 ← 0 bands), and out-of-phase NCO/NH 2 bend ( n 9 = 1 ← 0 bands) have been assigned. Molecular parameters have been obtained for the ground state and the unperturbed n 12 = 1 state. The least-squares fit calculations were completed with the microwave data available in the literature. The complicated resonance system between the n 12 = 2, n 11 = 1, and n 9 = 1 states has been investigated carefully. Thus, we have been able to verify almost all resonances (avoided crossing) existing in the region J, K investigated. In the coupled Hamiltonian used for the fit, all Watson’s reduced parameters, including the octic ones and 16 Coriolis coupling parameters were taken into account. The rms deviation obtained from the fit was 0.000247 cm −1.

Investigation of laser–plasma chemistry in CO–N 2–H 2O mixtures using 18O labeled water

A large-scale plasma was created in CO–N 2–H 2O gas mixtures by high-power laser-induced dielectric breakdown. The composition of the mixtures used corresponded to a cometary and/or meteoritic impact into the Earth’s early atmosphere. A multiple-centimeter-sized fireball was created by focusing near-infrared laser pulse into the centre of cell. The laser–plasma formation in the mixtures mainly leads to a production of CO 2. The competition of the CO + CO → CO 2 + C and CO + OH → CO 2 + H reactions in the CO 2 production was investigated using 18O labeled water. An analysis of the isotopomers was carried out by means of high-resolution FTIR spectroscopy.

Structure elucidation and NMR assignments for two amide alkaloids from a Mangrove endophytic Fungus (No. ZZF‐22)

The structure elucidations and complete (1)H and (13)C NMR assignments are reported for two new natural products: 3-benzylidene-8,8a-dihydroxy-2-methyl-hexahydro-pyrrolo[1,2-a]pyrazine-1,4-dione(1) and 4-hydroxy-6-(hydroxy-phenyl-methyl)-N-(3-methyl-butyryl)-nicotinamide (2). Both of these secondary metabolites were isolated from the fermentation medium of a Mangrove endophytic fungus. High resolution electron impact mass spectrometry (HREIMS), FT-IR Spectroscopy and NMR experiments including gCOSY, gHMQC, gHMBC and NOE were used for determination of the structures and assignments of the amide alkaloids.

FTIR spectra of the ν6 and ν8 bands of 13C formic acid molecule—Assignment of FIR-laser lines

Two interacting vibrational modes ν 6 and ν 8 of 13C species of formic acid have been studied with high resolution FTIR spectroscopy in the range 900–1300 cm −1 with an instrumental resolution of 0.0018 cm −1. More than 10 000 lines have been assigned and fitted with a RMS deviation of 0.00024 cm −1. The band centers, as well as the rotational, quartic and sextic centrifugal distortion parameters and 6 interaction parameters have been determined. The obtained parameters have enabled the assignments of 24 FIR laser emissions of this molecule observed previously by Dangoisse and Glorieux [D. Dangoisse, P. Glorieux, J. Mol. Spectrosc. 92 (1982) 283–297], Luis et al. [G.M.R.S. Luis, E.M. Telles, A. Scalabrin, D. Pereira, IEEE J. Quantum. Electron. QE-34 (1998) 767–769], and Bertolini et al. [A. Bertolini, G. Carelli, C.A. Massa, A. Moretti, F. Strumia, Infrared Phys. Technol. 40 (1999) 33–36].

Noncovalently Modified Carbon Nanotubes with Carboxymethylated Chitosan: A Controllable Donor-Acceptor Nanohybrid

We report here the modification of multiwalled carbon nanotubes (MWNTs) with a kind of polysaccharide, carboxymethylated chitosan (cmCs), and their potential usage as donor-acceptor nanohybrids. The modified composites (cmCs/MWNTs) were characterized by high-resolution TEM, FT-IR, TGA and time-resolved spectroscopy. The time-resolved spectroscopic experiments revealed that interfacial electron transfer readily takes place between MWNTs and surface immobilized cmCs chains. The forward electron transfer is fast (< 20 ns) while the backward recombination is slow. The recombination process strongly depends on the chain length of carboxylmethylated chitosan, i.e. a shorter recombination lifetime (~1.1 micros) for the shorter-chain cmCs coated MWNTs against that of the longer-chain cmCs coated MWNTs (~3.5 micros). The results demonstrated that the cmCs/MWNTs composite may be applied as a controllable donor-acceptor nanohybrid.

Spectroscopic constants of the ground and lower vibrational states of CH 281BrF: A combined high resolution infrared and microwave study

The enriched 81Br isotopic species of bromofluoromethane has been investigated in the infrared and microwave regions. The rovibrational spectrum of the ν 5 fundamental has been studied by high resolution FTIR spectroscopy, while the rotational spectra of the ground and v 6 = 1 states have been observed by means of microwave spectroscopy. More than 2700 transitions have been assigned in the ν 5 band and the analysis of the rovibrational structure reveals a first-order c-type Coriolis resonance with the v 6 = 2 state. The present study improves the ground state constants available in the literature and enables the determination of further centrifugal distortion parameters together with the full bromine quadrupole coupling tensor. A set of spectroscopic parameters up to the sextic distortion terms for the vibrational excited states has been accurately evaluated for the first time.

Temperature dependence of IR absorption of hydrous/hydroxyl species in minerals and synthetic materials

We report on temperature dependencies of infrared (IR) fundamental, combination, and overtone vibrations of hydroxyl species (OH) in nominally anhydrous minerals (e.g., titanite), ferroelectric crystals (KTa1-xNbxO3, KTN), layer silicates (talc, mica, and pyrophyllite), and hydrous minerals such as apatite and synthetic hydrous/deuterated garnets [Ca3Al2(O4H4)3 and Ca3Al2(O4D4)3] for the temperature range of 20-300 K. Data obtained by high-resolution FTIR spectroscopy show that increasing temperature generally leads to a decrease in the band height and band area of fundamental vibrations of hydroxyl species, whereas the combination and first-overtone bands commonly show different temperature dependencies. The results show that in the investigated temperature range, the variations of the band height and area for different OH bands (especially for combinations and overtones) on cooling or heating do not reflect changes in OH concentrations in the materials, but relate to temperature-dependent absorption coefficients. The observations imply that absorption coefficients calibrated at room temperature cannot necessarily be used for the determination of hydroxyl contents at other temperatures

High-Resolution FTIR, Microwave, and Ab Initio Investigations of CH279BrF: Ground, v5 = 1, and v6 = 1, 2 State Constants

A spectroscopic study of CH279BrF in the infrared and microwave regions has been carried out. The rovibrational spectrum of the nu5 fundamental interacting with 2nu6 has been investigated by high-resolution FTIR spectroscopy. Owing to the weakness of the 2nu6 band, the v6 = 2 state constants have been derived from v6 = 1. For this reason, the rotational spectra of the ground and v6 = 1 states have been observed by means of microwave spectroscopy. Highly accurate ab initio computations have also been performed at the CCSD(T) level of theory in order to support the experimental investigation. As far as the nu5 band is concerned, the analysis of the rovibrational structure led to the identification of more than 3000 transitions, allowing the determination of a set of spectroscopic parameters up to sextic distortion terms and pointing out first-order c-type Coriolis interaction with the v6 = 2 state. With regard to the pure rotational spectra measurements, the assignment of several DeltaJ = 0, +1 transitions allowed the determination of the rotational, all the quartic, and most of the sextic centrifugal distortion constants, as well as the full bromine quadrupole coupling tensor for both the ground and v6 = 1 states.